Why K2 inserts something in the url?

I never used K2, only the Joomla editor. I see no K2 items in K2 admin interface.

But from time to time I see in my url´s something as http://www.mydomain/en/k2-information/.... instead http://www.mydomain/en/.... Or http://mydomain/en/products/k2-media-manager/..../.... The site works normaly in both situations.
I already tried to build the part of the menu and the article (previously trashed and empty trash) completely new. No change, again and again this K2 spirit. Cache is cleared. It relates normal Joomla article and also RSForms, similar to that described here: http://www.joomlaworks.net/forum/k2-en/ ... ng-my-urls

I also tried to deinstall K2, but then 3/4 menus and articles in the site were deleted. I have no logic found. Once everything is ok, later I see the K2 in the url again.

Hi

K2 is a article source component. Our demo was build using them as an example, so some of the menu links can be referring to it's content. Try locate every menu item pointing to K2 component and remove them, so no urls will got affected.